As is known in the art, different wireless networks and/or systems of radios avoid interfering with each other by various options. For example, some systems rely on pre-arrangement or careful assignment of frequency bands, time slots, or signature pulses as is done for cellular systems through frequency reuse maps and time division multiple access (TDMA) for global system for mobile communications (GSM), orthogonal frequency division multiple access (OFDMA) for long term evolution (LTE), spread spectrum for IS-95, and combinations of these for wavelength carrier division multiple access (WCDMA) through HSPA commercial cellular standards. Other systems utilize collision avoidance techniques such as those employed for a-packet based systems such as IEEE 802.11/16/22 (WiFi and WiMax) where collisions are controlled as part of a multiple access medium access control procedure (e.g. carrier sense multiple access). Still other systems utilize so-called “on the fly” interference assessment and avoidance is used in operational paradigm for “cognitive radio” via dynamic spectrum access (DSA) for the newly allowed “secondary” user (see IEEE SCC41: Standards for Dynamic Spectrum Access Networks). This is done by the system of so-called “secondary user” radios actively sensing the radio spectrum and coordinating to choose an unused or empty band for transmission.
The existing systems, however, all fail if they are unable to avoid interference.
As the consumer market continues to rise for smart phones and wireless data service, the demand for more and more throughput increases drastically and the associated radio spectrum continues to become more crowded. A new paradigm in wireless communication is emerging where radios can be built to withstand interference to the level where interference is no longer avoided. Interference is allowed, even invited, to allow for more wireless devices to make use of the scarce free space in the wireless spectrum. For example, the LTE Advanced standard (to support heterogeneous HetNet network) allows, even encourages, interference. If a HetNet feature is enabled, reliable performance requires mobile devices to have some kind of interference mitigation in the receivers.
Conventional cognitive networks typically adapt at a network/routing layer, rather than a physical layer. Such networks typically “learn” which network nodes are having trouble sending packets through them and then they start to change how they route the packets. This conventional type of cognitive network does not invite or encourage interference; it simply does the best it can to avoid using links that are hindered by interference.